Abstract

The aim was to assess the role of Phragmites
australis (Cav.) Trin. ex Steud. in experimental,
mature, and temporarily flooded vertical flow wetland
filters treating urban runoff rich in organic matter.
During the experiment, ammonium chloride was
added to sieved concentrated road runoff to simulate
primary treated urban runoff contaminated with
nitrogen. Five days at 20°C N-allylthiourea biochemical
oxygen demand (BOD) and chemical oxygen
demand removal efficiencies were relatively lower for
planted than unplanted filters. Moreover, there was no
significant difference for BOD removal for all filters
under fluctuating inflow concentrations of sulfate.
The nitrogen removal performances of planted filters
were more efficient and stable throughout the seasons
compared to those of unplanted filters. A substantial
load of nitrogen (approximately 500 mg per filter)
was removed by harvesting P. australis. Plant uptake
was the main removal mechanism for nitrogen during
high concentrations (10 mg/L) of ammonia-nitrogen
in the urban runoff.